Constantine’s accession was a triumph for the civil aristocracy and was unfortunate in that he proved an incapable emperor. He reduced the army and neglected the frontier defenses at a time when the Seljuq Turks were pressing into the eastern provinces; consequently, the sultan Alp Arslan overran Armenia (1064–65) and attacked Caesarea (1067). In 1064 the Hungarians occupied Belgrade, and the Pechenegs (Patzinaks) and Uzes (Kumans) crossed the Danube River and ravaged the Balkan provinces, penetrating into Greece. In Italy the Normans were rapidly conquering the last remnants of the Byzantine possessions.

c. 1030 November 1072/January 1073 second sultan of the Seljuq Turks (1063–72), who inherited the Seljuq territories of Khorāsān and western Iran and went on to conquer Georgia, Armenia, and much of Asia Minor (won from the Byzantines).

a seminomadic, apparently Turkic people who occupied the steppes north of the Black Sea (8th–12th century) and by the 10th century were in control of the lands between the Don and lower Danube rivers (after having driven the Hungarians out); they thus became a serious menace to Byzantium....